A rotator cuff is a group of tendons in the shoulder joint that provides support and enables a wide range of motion. A major injury to these tendons may result in rotator cuff tears. It is one of the most common causes of shoulder pain in middle-aged and older individuals.
Throwing injuries of the shoulder are injuries sustained as a result of trauma by athletes during sports activities that involve repetitive overhand motions of the arm as in baseball, American football, volleyball, rugby, tennis, track and field events, etc.
Sports that involve overhead movements and repeated use of the shoulder at your workplace may lead to sliding of the upper arm bone from the glenoid. The dislocation might be a partial dislocation (subluxation) or a complete dislocation causing pain and shoulder joint instability.
Shoulder tendonitis is a condition characterized by inflammation of the tendons which connect the muscles to the shoulder bones. Tendonitis of the rotator cuff tendons is known as rotator cuff tendonitis. If the biceps tendon is affected, the condition is known as bicipital tendonitis.
Calcification tendinitis is a problem with the shoulder’s tendons and muscles. This condition occurs due to the formation of calcium deposits in the tendons (tissue which attaches muscle to bone) of the rotator cuff (a group of muscles and tendons stabilising the shoulder).
Osteoarthritis also called degenerative joint disease, is the most common form of arthritis. It occurs most often in older people. AC joint osteoarthritis affects the tissue covering the ends of bones (cartilage) in the AC joint of the shoulder. The cartilage becomes damaged and worn out causing pain, swelling, stiffness and restricted movement in the AC joint.
A dislocation occurs when the ends of your bones are partially or completely moved out of their normal position in a joint. A partial dislocation is referred to as a subluxation, whereas a complete separation is referred to as a dislocation.
The biceps muscle is the muscle of the upper arm which is necessary for the movement of the shoulder and elbow. It is made of a ‘short head’ and a ‘long head’ which function together. These are connected to the shoulder joint by two tendons called the proximal biceps tendons and to the elbow joint by a single distal biceps tendon.
Arthroscopy is a minimally invasive diagnostic and surgical procedure performed for joint problems. Shoulder arthroscopy is performed using a pencil-sized instrument called an arthroscope. The arthroscope consists of a light system and camera that projects images of the surgical site onto a computer screen for your surgeon to clearly view.
Triceps repair is a surgical procedure that involves the repair of a ruptured (torn) triceps tendon. A tendon is a tough band of fibrous tissue which connects muscle to bone and works together with muscles in moving your arms, fingers, legs, and toes. The triceps tendons connect the triceps muscles to the shoulder blade and elbow in your arm.
Acromioclavicular (AC) joint stabilisation is a surgical procedure employed to treat severe cases of AC joint dislocation.
AC joint dislocation is the separation of the collar bone or clavicle from the acromion (the top portion of the shoulder blade or scapula at the outer edge of the shoulder) due to severe trauma.
Shoulder separation can usually be managed by non-surgical treatments. In cases of a severe separation of the AC joint, your surgeon may perform a surgical repair or use a tissue graft to reconstruct the damaged ligaments. An autograft (from your own body) or allograft (from a donor) of the anterior tibia or hamstring may be used.
The labrum can sometimes tear during a shoulder injury. A specific type of labral tear that occurs when the shoulder dislocates is called a Bankart tear. This is a tear to a part of the labrum called the inferior glenohumeral ligament and is common in the young who sustain a dislocation of the shoulder.
Subacromial decompression is a surgical procedure performed for the treatment of a condition called shoulder impingement. In shoulder impingement, the degree of space between the rotator cuff tendon and shoulder blade is decreased due to irritation and swelling of the bursa or due to development of bone spurs.
The shoulder is prone to different kinds of injuries and inflammatory conditions. An intraarticular shoulder injection is a minimally invasive procedure to treat pain and improve shoulder movement. It may be performed with the help of ultrasound or fluoroscopic imaging which allows your physician to precisely target the intraarticular space.
Arthroscopic acromioplasty is performed using an arthroscope, a small, fibre-optic instrument consisting of a lens, light source, and video camera. The camera projects images of the inside of the joint onto a large monitor, allowing your surgeon to look for any damage, assess the injury, and perform the repair.
The biceps muscle is present on the front of your upper arm and functions to help you bend and rotate your arm. The biceps tendon is a tough band of connective fibrous tissue that attaches your biceps muscle to the bones in your shoulder on one side and the elbow on the other side.
The shoulder is the most flexible joint in the body that enables a wide range of movements including forward flexion, abduction, adduction, external rotation, internal rotation and 360-degree circumduction. Thus, the shoulder joint is considered the most insecure joint of the body, but the support of ligaments, muscles and tendons function to provide the required stability.
Bones of the Shoulder
The shoulder joint is a ball and socket joint made up of three bones, namely the humerus, scapula and clavicle.
The end of the humerus or upper arm bone forms the ball of the shoulder joint. An irregular shallow cavity in the scapula called the glenoid cavity forms the socket for the head of the humerus to fit in. The two bones together form the glenohumeral joint, which is the main joint of the shoulder.
Scapula and Clavicle
The scapula is a flat triangular-shaped bone that forms the shoulder blade. It serves as the site of attachment for most of the muscles that provide movement and stability to the joint. The scapula has four bony processes - acromion, spine, coracoid and glenoid cavity. The acromion and coracoid process serve as places for attachment of the ligaments and tendons.
The clavicle bone or collarbone is an S-shaped bone that connects the scapula to the sternum or breastbone. It forms two joints: the acromioclavicular joint, where it articulates with the acromion process of the scapula and the sternoclavicular joint where it articulates with the sternum or breast bone. The clavicle also forms a protective covering for important nerves and blood vessels that pass under it from the spine to the arms.
Soft Tissues of the Shoulder
The ends of all articulating bones are covered by smooth tissue called articular cartilage, which allows the bones to slide over each other without friction, enabling smooth movement. Articular cartilage reduces pressure and acts as a shock absorber during movement of the shoulder bones. Extra stability to the glenohumeral joint is provided by the glenoid labrum, a ring of fibrous cartilage that surrounds the glenoid cavity. The glenoid labrum increases the depth and surface area of the glenoid cavity to provide a more secure fit for the half-spherical head of the humerus.
Ligaments of the Shoulder
Ligaments are thick strands of fibres that connect one bone to another. The ligaments of the shoulder joint include:
Coracoclavicular ligaments: These ligaments connect the collarbone to the shoulder blade at the coracoid process.
- Acromioclavicular ligament: This connects the collarbone to the shoulder blade at the acromion process.
- Coracoacromial ligament: It connects the acromion process to the coracoid process.
- Glenohumeral ligaments: A group of 3 ligaments that form a capsule around the shoulder joint and connect the head of the arm bone to the glenoid cavity of the shoulder blade. The capsule forms a watertight sac around the joint. Glenohumeral ligaments play a very important role in providing stability to the otherwise unstable shoulder joint by preventing dislocation.
Muscles of the Shoulder
The rotator cuff is the main group of muscles in the shoulder joint and is comprised of 4 muscles. The rotator cuff forms a sleeve around the humeral head and glenoid cavity, providing additional stability to the shoulder joint while enabling a wide range of mobility.
The deltoid muscle forms the outer layer of the rotator cuff and is the largest and strongest muscle of the shoulder joint.
Tendons of the Shoulder
Tendons are strong tissues that join muscle to bone allowing the muscle to control the movement of the bone or joint. Two important groups of tendons in the shoulder joint are the biceps tendons and rotator cuff tendons.
Bicep tendons are the two tendons that join the bicep muscle of the upper arm to the shoulder. They are referred to as the long head and short head of the bicep.
Rotator cuff tendons are a group of four tendons that join the head of the humerus to the deeper muscles of the rotator cuff. These tendons provide more stability and mobility to the shoulder joint.
Nerves of the Shoulder
Nerves carry messages from the brain to muscles to direct movement (motor nerves) and send information about different sensations such as touch, temperature and pain from the muscles back to the brain (sensory nerves). The nerves of the arm pass through the shoulder joint from the neck. These nerves form a bundle at the region of the shoulder called the brachial plexus. The main nerves of the brachial plexus are the musculocutaneous, axillary, radial, ulnar and median nerves.
Blood vessels of the Shoulder
Blood vessels travel along with the nerves to supply blood to the arms. Oxygenated blood is supplied to the shoulder region by the subclavian artery that runs below the collarbone. As it enters the region of the armpit, it is called the axillary artery and further down the arm, it is called the brachial artery.
The main veins carrying de-oxygenated blood back to the heart for purification include:
- Axillary vein: This vein drains into the subclavian vein.
- Cephalic vein: This vein is found in the upper arm and branches at the elbow into the forearm region. It drains into the axillary vein.
- Basilic vein: This vein runs opposite the cephalic vein, near the triceps muscle. It drains into the axillary vein.